/* eslint-disable no-bitwise, no-mixed-operators, complexity */
const DECRYPT = 0
const ROUND = 32
const BLOCK = 16

const Sbox = [
    0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
    0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
    0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
    0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95, 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
    0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
    0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
    0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
    0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
    0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
    0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55, 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
    0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
    0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
    0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
    0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
    0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
    0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48
]

const CK = [
    0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
    0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
    0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
    0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
    0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
    0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
    0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
    0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
]

/**
 * 16 进制串转字节数组
 */
function hexToArray(str) {
    const arr = []
    for (let i = 0, len = str.length; i < len; i += 2) {
        arr.push(parseInt(str.substr(i, 2), 16))
    }
    return arr
}

/**
 * 字节数组转 16 进制串
 */
function ArrayToHex(arr) {
    return arr.map(item => {
        item = item.toString(16)
        return item.length === 1 ? '0' + item : item
    }).join('')
}

/**
 * utf8 串转字节数组
 */
function utf8ToArray(str) {
    const arr = []

    for (let i = 0, len = str.length; i < len; i++) {
        const point = str.codePointAt(i)

        if (point <= 0x007f) {
            // 单字节，标量值：00000000 00000000 0zzzzzzz
            arr.push(point)
        } else if (point <= 0x07ff) {
            // 双字节，标量值：00000000 00000yyy yyzzzzzz
            arr.push(0xc0 | (point >>> 6)) // 110yyyyy（0xc0-0xdf）
            arr.push(0x80 | (point & 0x3f)) // 10zzzzzz（0x80-0xbf）
        } else if (point <= 0xD7FF || (point >= 0xE000 && point <= 0xFFFF)) {
            // 三字节：标量值：00000000 xxxxyyyy yyzzzzzz
            arr.push(0xe0 | (point >>> 12)) // 1110xxxx（0xe0-0xef）
            arr.push(0x80 | ((point >>> 6) & 0x3f)) // 10yyyyyy（0x80-0xbf）
            arr.push(0x80 | (point & 0x3f)) // 10zzzzzz（0x80-0xbf）
        } else if (point >= 0x010000 && point <= 0x10FFFF) {
            // 四字节：标量值：000wwwxx xxxxyyyy yyzzzzzz
            i++
            arr.push((0xf0 | (point >>> 18) & 0x1c)) // 11110www（0xf0-0xf7）
            arr.push((0x80 | ((point >>> 12) & 0x3f))) // 10xxxxxx（0x80-0xbf）
            arr.push((0x80 | ((point >>> 6) & 0x3f))) // 10yyyyyy（0x80-0xbf）
            arr.push((0x80 | (point & 0x3f))) // 10zzzzzz（0x80-0xbf）
        } else {
            // 五、六字节，暂时不支持
            arr.push(point)
            throw new Error('input is not supported')
        }
    }

    return arr
}

/**
 * 字节数组转 utf8 串
 */
function arrayToUtf8(arr) {
    const str = []
    for (let i = 0, len = arr.length; i < len; i++) {
        if (arr[i] >= 0xf0 && arr[i] <= 0xf7) {
            // 四字节
            str.push(String.fromCodePoint(((arr[i] & 0x07) << 18) + ((arr[i + 1] & 0x3f) << 12) + ((arr[i + 2] & 0x3f) << 6) + (arr[i + 3] & 0x3f)))
            i += 3
        } else if (arr[i] >= 0xe0 && arr[i] <= 0xef) {
            // 三字节
            str.push(String.fromCodePoint(((arr[i] & 0x0f) << 12) + ((arr[i + 1] & 0x3f) << 6) + (arr[i + 2] & 0x3f)))
            i += 2
        } else if (arr[i] >= 0xc0 && arr[i] <= 0xdf) {
            // 双字节
            str.push(String.fromCodePoint(((arr[i] & 0x1f) << 6) + (arr[i + 1] & 0x3f)))
            i++
        } else {
            // 单字节
            str.push(String.fromCodePoint(arr[i]))
        }
    }

    return str.join('')
}

/**
 * 32 比特循环左移
 */
function rotl(x, n) {
    const s = n & 31
    return (x << s) | (x >>> (32 - s))
}

/**
 * 非线性变换
 */
function byteSub(a) {
    return (Sbox[a >>> 24 & 0xFF] & 0xFF) << 24 |
        (Sbox[a >>> 16 & 0xFF] & 0xFF) << 16 |
        (Sbox[a >>> 8 & 0xFF] & 0xFF) << 8 |
        (Sbox[a & 0xFF] & 0xFF)
}

/**
 * 线性变换，加密/解密用
 */
function l1(b) {
    return b ^ rotl(b, 2) ^ rotl(b, 10) ^ rotl(b, 18) ^ rotl(b, 24)
}

/**
 * 线性变换，生成轮密钥用
 */
function l2(b) {
    return b ^ rotl(b, 13) ^ rotl(b, 23)
}

/**
 * 以一组 128 比特进行加密/解密操作
 */
function sms4Crypt(input, output, roundKey) {
    const x = new Array(4)

    // 字节数组转成字数组（此处 1 字 = 32 比特）
    const tmp = new Array(4)
    for (let i = 0; i < 4; i++) {
        tmp[0] = input[4 * i] & 0xff
        tmp[1] = input[4 * i + 1] & 0xff
        tmp[2] = input[4 * i + 2] & 0xff
        tmp[3] = input[4 * i + 3] & 0xff
        x[i] = tmp[0] << 24 | tmp[1] << 16 | tmp[2] << 8 | tmp[3]
    }

    // x[i + 4] = x[i] ^ l1(byteSub(x[i + 1] ^ x[i + 2] ^ x[i + 3] ^ roundKey[i]))
    for (let r = 0, mid; r < 32; r += 4) {
        mid = x[1] ^ x[2] ^ x[3] ^ roundKey[r + 0]
        x[0] ^= l1(byteSub(mid)) // x[4]

        mid = x[2] ^ x[3] ^ x[0] ^ roundKey[r + 1]
        x[1] ^= l1(byteSub(mid)) // x[5]

        mid = x[3] ^ x[0] ^ x[1] ^ roundKey[r + 2]
        x[2] ^= l1(byteSub(mid)) // x[6]

        mid = x[0] ^ x[1] ^ x[2] ^ roundKey[r + 3]
        x[3] ^= l1(byteSub(mid)) // x[7]
    }

    // 反序变换
    for (let j = 0; j < 16; j += 4) {
        output[j] = x[3 - j / 4] >>> 24 & 0xff
        output[j + 1] = x[3 - j / 4] >>> 16 & 0xff
        output[j + 2] = x[3 - j / 4] >>> 8 & 0xff
        output[j + 3] = x[3 - j / 4] & 0xff
    }
}

/**
 * 密钥扩展算法
 */
function sms4KeyExt(key, roundKey, cryptFlag) {
    const x = new Array(4)

    // 字节数组转成字数组（此处 1 字 = 32 比特）
    const tmp = new Array(4)
    for (let i = 0; i < 4; i++) {
        tmp[0] = key[0 + 4 * i] & 0xff
        tmp[1] = key[1 + 4 * i] & 0xff
        tmp[2] = key[2 + 4 * i] & 0xff
        tmp[3] = key[3 + 4 * i] & 0xff
        x[i] = tmp[0] << 24 | tmp[1] << 16 | tmp[2] << 8 | tmp[3]
    }

    // 与系统参数做异或
    x[0] ^= 0xa3b1bac6
    x[1] ^= 0x56aa3350
    x[2] ^= 0x677d9197
    x[3] ^= 0xb27022dc

    // roundKey[i] = x[i + 4] = x[i] ^ l2(byteSub(x[i + 1] ^ x[i + 2] ^ x[i + 3] ^ CK[i]))
    for (let r = 0, mid; r < 32; r += 4) {
        mid = x[1] ^ x[2] ^ x[3] ^ CK[r + 0]
        roundKey[r + 0] = x[0] ^= l2(byteSub(mid)) // x[4]

        mid = x[2] ^ x[3] ^ x[0] ^ CK[r + 1]
        roundKey[r + 1] = x[1] ^= l2(byteSub(mid)) // x[5]

        mid = x[3] ^ x[0] ^ x[1] ^ CK[r + 2]
        roundKey[r + 2] = x[2] ^= l2(byteSub(mid)) // x[6]

        mid = x[0] ^ x[1] ^ x[2] ^ CK[r + 3]
        roundKey[r + 3] = x[3] ^= l2(byteSub(mid)) // x[7]
    }

    // 解密时使用反序的轮密钥
    if (cryptFlag === DECRYPT) {
        for (let r = 0, mid; r < 16; r++) {
            mid = roundKey[r]
            roundKey[r] = roundKey[31 - r]
            roundKey[31 - r] = mid
        }
    }
}

function sm4(inArray, key, cryptFlag, {
    padding = 'pkcs#7', mode, iv = [], output = 'string'
} = {}) {
    if (mode === 'cbc') {
        // CBC 模式，默认走 ECB 模式
        if (typeof iv === 'string') iv = hexToArray(iv)
        if (iv.length !== (128 / 8)) {
            // iv 不是 128 比特
            throw new Error('iv is invalid')
        }
    }

    // 检查 key
    if (typeof key === 'string') key = hexToArray(key)
    if (key.length !== (128 / 8)) {
        // key 不是 128 比特
        throw new Error('key is invalid')
    }

    // 检查输入
    if (typeof inArray === 'string') {
        if (cryptFlag !== DECRYPT) {
            // 加密，输入为 utf8 串
            inArray = utf8ToArray(inArray)
        } else {
            // 解密，输入为 16 进制串
            inArray = hexToArray(inArray)
        }
    } else {
        inArray = [...inArray]
    }

    // 新增填充，sm4 是 16 个字节一个分组，所以统一走到 pkcs#7
    if ((padding === 'pkcs#5' || padding === 'pkcs#7') && cryptFlag !== DECRYPT) {
        const paddingCount = BLOCK - inArray.length % BLOCK
        for (let i = 0; i < paddingCount; i++) inArray.push(paddingCount)
    }

    // 生成轮密钥
    const roundKey = new Array(ROUND)
    sms4KeyExt(key, roundKey, cryptFlag)

    const outArray = []
    let lastVector = iv
    let restLen = inArray.length
    let point = 0
    while (restLen >= BLOCK) {
        const input = inArray.slice(point, point + 16)
        const output = new Array(16)

        if (mode === 'cbc') {
            for (let i = 0; i < BLOCK; i++) {
                if (cryptFlag !== DECRYPT) {
                    // 加密过程在组加密前进行异或
                    input[i] ^= lastVector[i]
                }
            }
        }

        sms4Crypt(input, output, roundKey)


        for (let i = 0; i < BLOCK; i++) {
            if (mode === 'cbc') {
                if (cryptFlag === DECRYPT) {
                    // 解密过程在组解密后进行异或
                    output[i] ^= lastVector[i]
                }
            }

            outArray[point + i] = output[i]
        }

        if (mode === 'cbc') {
            if (cryptFlag !== DECRYPT) {
                // 使用上一次输出作为加密向量
                lastVector = output
            } else {
                // 使用上一次输入作为解密向量
                lastVector = input
            }
        }

        restLen -= BLOCK
        point += BLOCK
    }

    // 去除填充，sm4 是 16 个字节一个分组，所以统一走到 pkcs#7
    if ((padding === 'pkcs#5' || padding === 'pkcs#7') && cryptFlag === DECRYPT) {
        const len = outArray.length
        const paddingCount = outArray[len - 1]
        for (let i = 1; i <= paddingCount; i++) {
            if (outArray[len - i] !== paddingCount) throw new Error('padding is invalid')
        }
        outArray.splice(len - paddingCount, paddingCount)
    }

    // 调整输出
    if (output !== 'array') {
        if (cryptFlag !== DECRYPT) {
            // 加密，输出转 16 进制串
            return ArrayToHex(outArray)
        } else {
            // 解密，输出转 utf8 串
            return arrayToUtf8(outArray)
        }
    } else {
        return outArray
    }
}

function encrypt(inArray, key, options) {
    return sm4(inArray, key, 1, options)
}
function decrypt(inArray, key, options) {
    return sm4(inArray, key, 0, options)
}